Shafter Lake takes its name from a lake feature in northwestern Andrews County and produces from the Permian San Andres dolomite of the Central Basin Platform. It was opened in the middle 1940s, at the start of the county’s most intense development period, when twenty-six new fields were found in that decade and ninety more in the one that followed. Like nearly every San Andres field in the county, it has spent most of its producing life under waterflood and is a mature, injection-supported property today.
Source: Texas Railroad Commission production filings, aggregated across RRC field designations 82570100, 82570200, 82570300, 82570500, 82570600, 82570700. Reported volumes lag the calendar by several months.
Andrews County oil begins on December 5, 1929, when the Deep Rock Ogden No. 1 came in at 4,345 feet. The market crash and the flood of East Texas crude that followed pushed prices toward ten cents a barrel by 1931, so the county developed slowly at first, with only five new fields opened during the entire 1930s. What the decade did establish was that the San Andres dolomite underlay a very large area at drillable depth, which set up everything that came afterward.
The pace changed after the war. Twenty-six new fields were developed in Andrews County during the 1940s, and Shafter Lake belongs to that group. County population rose from 1,277 in 1940 to more than 5,000 by 1950 as drilling crews, service companies and their families moved in. Ninety more fields followed in the 1950s and fifty-three in the 1960s. Few counties anywhere have been drilled as systematically or as completely as Andrews was in those three decades.
Waterflooding followed primary production as reservoir pressure fell, and it has carried the county’s San Andres fields ever since. By 1982 Andrews County had produced more than two billion barrels cumulatively, and by the end of 2004 the figure reached 2,783,911,447 barrels since 1929. Production continues at a fraction of peak rates, sustained by injection, workovers and the continual reworking of old wellbores. Shafter Lake fits that pattern precisely, and owners should expect a long tail rather than growth.
Shafter Lake produces from the Permian San Andres formation, a shallow-water dolomite deposited across the Central Basin Platform in tidal-flat and shallow marine settings. Porosity is moderate, permeability is uneven, and the section is layered, with tight streaks separating the better pay intervals. Traps combine gentle structural closure with lateral changes in reservoir quality, which is why field boundaries in this part of the county are defined as much by porosity development as by structure. The dolomite is shallow enough that both drilling and workovers have always been comparatively cheap.
Waterflooding is the mechanism behind Shafter Lake’s longevity. Injection restores pressure lost to primary depletion and displaces oil toward producing wells, and San Andres floods on the platform have historically recovered a substantial additional share of the oil originally in place. The perennial issue is vertical conformance, because injected water enters the most permeable layer first and can bypass pay above and below it. Operators respond with selective completions, profile control and pattern conversions. Andrews County’s dense injection infrastructure keeps that maintenance affordable.
Shafter Lake interests are unit royalties from a mature flood, so value rests on the performance of the particular units your tract participates in rather than on any drilling forecast. Andrews County is one of the most heavily solicited counties in Texas for mineral purchases, and unsolicited offers here often arrive without any statement of which units are being priced. Insisting on that detail is the single best protection an owner has. We buy minerals and royalties in Andrews County and provide free written offers.
County-level well data, production charts, and selling guides for the counties this field spans:
A serious offer identifies the specific units, leases and decimals it is pricing, states whether it is buying all depths or only producing horizons, and comes in writing. Offers that name a lump sum without listing what is being bought are impossible to compare and often exclude interests you own. Ask for the property list first, every time.
In a waterflood unit, no. Production is allocated across the whole unit by a participation formula, and your decimal reflects your share of that formula. A new well or a workover anywhere in the unit affects your check, and a well right on your tract does not necessarily pay you more than one a mile away.
Your mineral or royalty ownership does not change; only the party paying you does. You will usually receive a new division order or a letter from the buyer. The practical thing to watch is whether the new operator continues investing in injection and workovers, because in a mature flood that decision drives your income more than anything else.