On the Problem of Relaxation of the Jurassic Basin of the Mastakh Gas-Condensate Field

Chernenko V.B., Sivtsev A.I.


An analysis of the development of the Jurassic deposit of  Mastakh gas-condensate field of the Hapchagay megalithic bank of  the Viluy syneclise is done. The gas recovery factor after the termination of development of the reservoir J1-I amounted 34% of the gas resources approved in the State Reserves Committee of  the USSR. It is concluded that the low recovery factor is brought about by uneven and intensive selection of gas from the reservoir which led to drawing cones of water to the production wells and their premature watering. Some isolated results of measurements of the reservoir pressure from observation wells for the period since 2003 to 2013 year are given. It is established a measurable dynamics of the formation pressure relaxation (up to 0.12 MPa/year). A variety of different reasons of the observed recovery of formation pressure are discussed. As the most  probable reasons a redistribution of  trapped gas volumes, technogenic cross-flows and degassing of bottom waters are considered. It is recommended to undertake a study of the gas-condensate deposit in order to reveal a gas composition change for fixing probable gas cross-flows between beds. The dynamics of formation temperature is given, that also have a trend to appreciable increase (up to 4°C). The necessity of making corrections in the regimes of development of the gas-condensate fields of Hapchagaysky megaswell is marked.


Key words: deposit, analysis of the development, reservoir pressure, trapped gas volumes, technogenic cross-flows, degassing.

Science and Education, 2015, No.1, pp.16-21